Dual Reactivity of Step-Bound Carbon Monoxide during Oxidation on a Stepped Platinum Electrode in Alkaline Media

The electrooxidation of adsorbed CO on a stepped platinum electrode in alkaline media reveals a dual role of the active step site in activating CO oxidation by adsorbed OH. The combination of interrupted chronoamperometry with cyclic voltammetry shows that there is active combination of CO and OH near or on the step site as well as a much less reactive combination of CO and OH in which the CO sits on the step and reacts with OH from the terrace.